The Adams Room is open for breakfast and lunch 6:30 a.m. to 3 p.m. Monday through Friday, for brunch 10:30 a.m. to 3 p.m. Saturday and Sunday. The John Hay Room is open for lunch 11:30 a.m. to 2:30 p.m. Monday through Friday, for dinner 5:30 p.m. to 11 p.m. daily. (No weekend luncheon.) The Grill Room is open for lunch 11:30 a.m. to 2:30 p.m., for dinner 5:30 p.m. to 11 p.m. Reservations are suggested for the Hay and Adams rooms. MC, AE, DC, CB, MC, V. Prices: Luncheon prices $14 to $22, brunch prices $10 to $22. At dinner appetizers $4 to $18, main dishes $14 to $23, desserts $6. Full dinner with wine, tax and tip $50 or more per person.

One can understand why hotel restaurants might be more inconsistent than ordinary restaurants, since they must operate seven days a week from breakfast through dinner and deal with banquets and room service as well as dining room guests. What can't be readily understood is why hotels charge so much for their inconsistent services.

Why are the oysters Rockefeller $12 at the Hay-Adams? Is there a special reason why the spinach salad should be $7 because it is in a hotel, or the onion soup $5, the coquilles St. Jacques $17, the liver $15 and the grenadin of veal $22? And why are the wine prices substantially above those at many other elegant restaurants?

The answer should be that fine food from a talented chef -- in this case, the former chef of the British Embassy -- is worth top prices. But that answer doesn't work here because what you are served in the Hay-Adams is typical hotel food: grand, handsome presentations of generally high quality ingredients prepared with no more personality and precision than banquet food.

I had a special advantage at the Hay-Adams in that the staff knew me as a restaunt critic. Furthermore, I visited more than half a dozen times, at all times of the day and days of the week to give it every chance to prove its mettle.

My conclusion after all that: You can dine well at the Hay- Adams, but only if you are careful to order nothing more exotic than smoked salmon as an appetizer ($12), plain broiled lamb chops ($19) and coffee ($2.25). In the stunningly handsome English Grill downstairs, with its carved wood ceiling and leaded glass windows, you can find an exceptional version of Scotch Egg, that pub dish of hard-cooked egg wrapped in sausage. The stilton fritters are an appealing appetizer, and the lemon tart is a delicately excellent dessert. There are other highlights, but nothing you could predict, and you can certainly dine dismally for the price of a plane ticket to New York.

Beef wellington has been considered a specialty in the Hay- Adams dining room, but it was one of the soggiest pastries I have encountered, and the beef tasted steamed as thoroughly as a pot roast. Quenelles -- on the menu called Mousseline of Salmon and Sole -- are a standard preparation for such an international kitchen. Here they were dense and rubbery, in a gluey sauce that, to its credit, did taste pleasantly enough of lobster. Another day a salmon mousse made a better showing, but it too was firm and grainy. And in the Grill the dry, gray roast beef was reminiscent of the beef wellington. Even more dismal was a soggy, insipid chicken pot pie (which arrived accompanied by some rather nice fresh cauliflower).

In all, the meals have been consistent only in having both ups and downs -- carefully timed, sweetly fresh trout sharing the table with duck whose crisp skin covered stringy and soggy meat, made soggier by an overdose of Grand Marnier. A fine rendition of herbed shrimp with tomato concasse came after snails that were dreadful -- dried out and acrid. Canned snails are not easy to ruin.

Usually a few visits to a restaurant allow you to generalize: this chef does well with fish but shows less care with meat, yne might say at one place. Or at another you might learn not to order cream sauces, or conclude that lunch is better than dinner. No such lessons were apparent at the Hay-Adams. It was as if each meal was a whole new ball game. A light and pretty vegetable,e one day was studded with the tiniest green beans and broccoli bits and bound with a subtle and soft chicken mousse; another time the chicken mousse was dry and chewy. At times lobster bisque has tasted excellent -- intense, rich, spicy and creamy -- and cream of asparagus soup has arrived richly green and tasting of spring, both offerings showing a kitchen willing to take pains with standard menu items. But oysters Rockefeller were obviously shells filled with oysters other than their own -- most likely from a jar -- though their spinach topping had a zesty flavor and nice bite to the texture. Pleasantly crusty and rare london boil with a respectable mushroom sauce was offset by crab cakes leaded with a thick, floury b,echamel and crab meat reduced to shreds. The trolley of desserts looks impressive, but my samples proved soggy and stolid, with maybe a decent chocolate mousse here or some unimpeachable raspberries there. At brunch one afternoon the scones were soft and decent, the croissants doughy and gummy.

Actually, brunch and breakfast show the Hay-Adams at its best, for far more enticing than the food are the furnishings and the little extras. A morning meal in a sunny room overlooking the White House, with yellow silk moire walls intensifying the sunlight, is Washington at its most glorious. Flowers are sumptuous, tableware is intensely pretty, and there are charming touches such as an assortment of teabags to accompany your fat china teapot (though the tea would be better if the bags were inserted when the water was fresh off the stove, or if the tea were loose). Butter is in sweet rosettes, and the citrus juices are freshly squeezed. The kitchen poaches eggs impeccably, to the benefit of the eggs benedict and the perfectly good corned beef hash. And beverage service is a lovely ceremony, from the thoroughly proper champagne cocktail to the gleaming silver coffee pots with excellent coffee.

Even for dinner the main dining room is an experience worth something in itself, with its intricately decorative ceiling and stunningly handsome wood paneling inset with leaded glass. There are tapestries on the walls and brocade on the high-back chairs. On the tables are small, brass-shaded lamps and gilded china. It is a marvelous Old World dining room.

One evening I had salmon, a fillet that was pearly pink and grilled with appealing crosshatch marks to the perfect velvety state just beyond raw. It was surrounded by a pretty-as-a-garden mixture of minced red and green peppers with mint, a crunchy raw contrast that enhanced the delicately fresh fish without overwhelming it. And on the side was a gentle beurre blanc lightly touched with mint. It was a spectacular dish. It has not been repeated or even challenged on any of my visits to the Hay-Adams since. Whatever was going on in the kitchen that night ought to be encouraged every night.

-- Phyllis C. Richman TURNING TABLES

Dad's Severest Critic? -- Why, we wondered, were there Rice Krispies on the bar at Ivy's Place? They were there for Ivy, the Indonesian and Thai restaurant's namesake, the 6-year-old daughter of owner Martin Benjamin, the bartender said. Turns out that Ivy likes Italian food from the restaurant next door, too.